DE102014200416A1 - Apparatus and method for exciting a resolver - Google Patents

Abstract

An electrical signal generator (Q) for operating a field winding (WE) of a resolver (R), wherein the resolver (R) has at least one sensor winding (WS, WS ') which generates a sensor voltage (WE) in response to the operation of the field winding (WE). Us, Us') has: a monitoring device (Vü) for receiving a sensor signal (Sa, Sa ') representing the sensor voltage (Us, Us') for determining a strength (| S |) of a component of the sensor signal (Sa, Sa ') and for generating a monitoring signal (Sü) is formed, which contains information about the determined strength (| S |) of the component of the sensor signal (Sa, Sa'); and - an output unit (QA), which is designed to provide an electrical signal (I, U) for operating the excitation winding (WE) and in dependence of the monitoring signal (Sü) an amplitude (^ I, ^ U) of the electrical signal ( I, U), if the determined strength (| S |) of the component of the sensor signal (Sa, Sa ') exceeds a predetermined first threshold value (SW1) and / or in dependence of the monitoring signal (Sü) has an amplitude (| ^ U) of the electrical signal (I, U) to increase when the determined strength (| S |) of the component of the sensor signal (Sa, Sa ') below a predetermined second threshold (SW2).

Description

The invention relates to an electrical signal generator for operating an exciter winding of a resolver, a circuit arrangement with a resolver and with a resolver control, a motor vehicle with a circuit arrangement and a method for operating a resolver.

A "resolver" is an electromagnetic transducer for converting an angular position of a rotor relative to a stator into an electrical variable.

Typically, resolvers each comprise a stator winding for a total of two stator phases and exactly one rotor winding. In principle, however, other arrangements are known, for example, with more than two stator phases, or resolver, in which two rotor windings are provided for each rotor phase, but only exactly one stator winding. In addition, a distinction is made between circuit arrangements in which the resolver is excited on the rotor side and circuit arrangements in which the resolver is excited on the stator side.

In the usual configuration, in which exactly one rotor winding and two stator windings are provided, the excitation of the resolver takes place either single-phase by means of the rotor winding or two-phase by means of the two stator windings. In the first case, the rotor serves as a donor for a direction-changing magnetic alternating field and the two stator windings as sensors for the direction-changing magnetic alternating field (whose direction is to be determined by means of the sensors). In the second case, the two stator windings serve as donors for a directionally variable magnetic alternating field and the one rotor winding as a sensor for the directionally variable magnetic alternating field. For resolvers, measuring methods based on the use of the Doppler effect, measuring methods based on amplitude modulation and measuring methods based on phase modulation are known.

One from the DE 1 298 298 A Known angle measuring device has a rotor with a rotor winding and a stator with two mutually perpendicular stator windings. An alternating magnetic field whose direction is synchronous with the angular position is generated by supplying a sine wave to the rotor winding. The alternating magnetic field induces in each of the two stator windings each a voltage signal whose respective amplitude is dependent on the angular position of the rotatable shaft. The induced voltages in the two sensor windings are amplitude modulated. The measuring method described there is based overall on phase modulation. The phase demodulation is performed here as follows: By means of zero indicators, a clock and a clock counter, times are measured between zero crossings of an original sine voltage and zero crossings of the voltage signals. From the measured times, the angular position of the rotatable shaft is determined and digitally coded.

A disadvantage of the known resolvers is that they do not allow reliable angle measurement with faulty sensor voltages.

The object of the present invention is to provide improved devices and methods with which the abovementioned disadvantages are at least partially avoided.

This object is achieved by the electrical signal generator according to the invention according to claim 1, the circuit arrangement according to claim 7, the motor vehicle according to claim 8 and the method according to claim 10.

• – eine Überwachungsvorrichtung, die zum Empfangen eines die Sensorspannung repräsentierenden Sensorsignals, zum Ermitteln einer Stärke eines Bestandteils des Sensorsignals und zum Erzeugen eines Überwachungssignals ausgebildet ist, das eine Information über die ermittelte Stärke des Bestandteils des Sensorsignals enthält; und
• – eine Ausgangseinheit, die dazu ausgebildet ist, ein elektrisches Signal zum Betreiben der Erregerwicklung bereitzustellen und in Abhängigkeit des Überwachungssignals eine Amplitude des elektrischen Signals zu verringern, wenn die ermittelte Stärke des Bestandteils des Sensorsignals einen vorgegebenen ersten Schwellenwert überschreitet und/oder in Abhängigkeit des Überwachungssignals eine Amplitude des elektrischen Signals zu vergrößern, wenn die ermittelte Stärke des Bestandteils des Sensorsignals einen vorgegebenen zweiten Schwellenwert unterschreitet.

According to a first aspect, the present invention relates to an electrical signal generator for operating an exciter winding of a resolver, wherein the resolver has at least one sensor winding, which outputs a sensor voltage in response to the operation of the excitation winding. The electrical signal generator comprises:

• A monitoring device, which is designed to receive a sensor signal representing the sensor voltage, to determine a strength of a component of the sensor signal and to generate a monitoring signal which contains information about the determined strength of the component of the sensor signal; and
• - An output unit which is adapted to provide an electrical signal for operating the exciter winding and to reduce depending on the monitoring signal, an amplitude of the electrical signal when the determined strength of the component of the sensor signal exceeds a predetermined first threshold and / or in response to the monitoring signal increase an amplitude of the electrical signal when the determined strength of the component of the sensor signal falls below a predetermined second threshold value.

According to a second aspect, the present invention relates to a circuit arrangement with a resolver, which has an excitation winding and at least one sensor winding, and with a resolver control, wherein the resolver control comprises an electrical signal generator according to the first aspect and at least one analog-digital Transducer with the at least one sensor winding for receiving the sensor voltage and wherein the first and / or the second threshold represent an operating range of the at least one analog-to-digital converter.

According to a third aspect, the present invention relates to a motor vehicle having a circuit arrangement according to the second aspect.

• – Betreiben der Erregerwicklung mit einem elektrischen Signal;
• – Erfassen der Sensorspannung;
• – Erzeugen eines Sensorsignals auf Grundlage der erfassten Sensorspannung;
• – Ermitteln einer Stärke eines Bestandteils des Sensorsignals;
• – Erzeugen eines Überwachungssignals, das eine Information über die ermittelte Stärke des Bestandteils des demodulierten Sensorsignals enthält;
• – Verringern einer Amplitude des elektrischen Signals in Abhängigkeit des Überwachungssignals, wenn die ermittelte Stärke des Bestandteils des Sensorsignals einen vorgegebenen ersten Schwellenwert überschreitet, und/oder
• – Vergrößern einer Amplitude des elektrischen Signals in Abhängigkeit des Überwachungssignals, wenn die ermittelte Stärke des Bestandteils des Sensorsignals einen vorgegebenen zweiten Schwellenwert unterschreitet.

According to a fourth aspect, the present invention relates to a method of operating a resolver, the resolver having a field winding and at least one sensor winding that outputs a sensor voltage in response to the driving of the field winding, the method comprising the steps of:

• - Operating the exciter winding with an electrical signal;
• - Detecting the sensor voltage;
• Generating a sensor signal based on the detected sensor voltage;
• - determining a strength of a component of the sensor signal;
• - generating a monitoring signal containing information about the detected strength of the component of the demodulated sensor signal;
• - Reducing an amplitude of the electrical signal in response to the monitoring signal when the determined strength of the component of the sensor signal exceeds a predetermined first threshold, and / or
• - Increasing an amplitude of the electrical signal in response to the monitoring signal when the determined strength of the component of the sensor signal falls below a predetermined second threshold.

Further advantageous embodiments of the invention will become apparent from the subclaims and the following description of preferred embodiments of the present invention.

Regardless of the basic structure of the resolver is constructed and based on which of the above-exemplified measurement principles of the resolver, it was found that the induced signal in a sensor winding signal can not be evaluated if at the sensor winding or at a terminal of the sensor winding (for example an insulation fault) a shunt has arisen.

In drive units of machines (such as machine tools) or vehicles, especially motor vehicles, the rotation angle or speed information of the resolver may be required for the operation of the drive unit. In motor vehicles, resolvers are used, for example, for detecting the position of electric traction drives and for detecting the position of electromechanical steering systems. Therefore, a non-evaluability of the measurement signal of a sensor winding as a result of a shunt to a malfunction of the drive unit or the steering system and thus lead to an availability limitation of the engine or the motor vehicle.

Similar problems can arise when errors occur which reduce the amplitude of the voltage induced in the sensor winding to a value which is below a tolerance range provided in any case. Examples include: too small a transmission ratio between the field winding and the sensor winding (for example due to a short circuit in the sensor winding), mechanical tolerances, excessive contact resistance (for example at a solder joint or a plug contact) or corrosion damage. It is also possible that errors occur which increase the amplitude of the voltage induced in the sensor winding to a value which is above an already provided tolerance range. Examples of this are: too high a transmission ratio (for example, due to a short circuit in the excitation winding).

A concept of the invention can be seen in that the amplitude of the excitation current or the excitation voltage is changed, reduced or increased in dependence on an error pattern of the demodulated sensor signal. Thus, in contrast to known generic devices, at least for certain fault scenarios (which occur in practice), it is possible to continue to use the resolver, despite an error, for providing rotational angle information and / or for providing rotational speed information. As a result, for example, a machine or a (power) vehicle that requires rotational angle or rotational speed information of the resolver for operation can continue to be used. The further use can also happen in an emergency operation. A machine or vehicle user can thus be spared inconvenience that would be associated with a stoppage of the machine or the vehicle. The detected error can then be noted, for example in the background (that is to say without informing the machine or vehicle user) as a diagnostic date and remedied as part of routine maintenance. In some application scenarios, it may be appropriate (for safety reasons, for example) to inform the machine or vehicle user about the initiation of emergency operation (for example by means of a warning).

Some embodiments accordingly relate to an electrical signal generator for operating a field winding of a resolver. The resolver has next to the at least one The excitation winding also has at least one sensor winding which, in response to the operation of the exciter winding, outputs a sensor voltage which is induced accordingly, as stated above. The present invention is not intended for a particular embodiment of the resolver. As stated above, the resolver can be used for angle measurement, e.g. B. in a machine or in a motor vehicle. He can he used to Lage- or speed measurement in an electric machine that drives the motor vehicle or parts thereof, such as a steering.

The signal generator comprises a monitoring device which is designed to receive a sensor signal representing the sensor voltage, to determine a strength of a component of the sensor signal and to generate a monitoring signal which contains information about the determined strength of the component of the sensor signal. The monitoring device can, for. B. u. a. a microprocessor or the like, which is submitted to perform said functions.

The sensor signal may originate, for example, from an analog-to-digital converter of a resolver controller, which receives the sensor voltage of the at least one sensor coil and converts it into a digital sensor signal. The digital sensor signal may also be fed to a demodulator which demodulates the digital sensor signal. Accordingly, the sensor signal may also be a digital, demodulated sensor signal.

The electrical signal generator also includes an output unit configured to provide an electrical signal to operate the field winding. The electrical signal may be a voltage signal or a current signal which supplies the excitation winding with electrical energy, in particular an exciter current or an exciter voltage. The electrical signal can z. B. sinusoidal or cosinusoidal or have a different course, which is useful for the excitation of the exciter winding of the resolver. The output unit is further configured to reduce an amplitude of the electrical signal as a function of the monitoring signal if the determined strength of the component of the sensor signal exceeds a predetermined first threshold value and / or increase an amplitude of the electrical signal in response to the monitoring signal, if the determined Strength of the component of the sensor signal falls below a predetermined second threshold. Although here the electric signal generator has an output unit and a monitoring unit, the output unit and the monitoring unit can also be realized together in one unit, for. B. by a microprocessor with appropriate electronics. Consequently, the output unit and the monitoring unit are to be understood functionally, whose functions can be performed by a single unit.

As stated above, an amplitude of the sensor signal can be configured such that it can not be evaluated. This can be z. B. happen that the amplitude of the sensor voltage is partially or even completely outside of a working range of an analog-to-digital converter, which converts the sensor voltage into a digital sensor signal, as already mentioned above. The operating range of the analog-to-digital converter typically has an upper and a lower limit, so that amplitudes of an incoming voltage signal that exceed the upper or lower limit can not be digitized, but z. B. be cut off. Accordingly, information is lost. Therefore, the monitoring device analyzes the received sensor signal and recognizes z. B. that an amplitude was cut off at the top and / or bottom. This can be z. B. be detected on the basis of the discontinuous change in the signal waveform of the sensor signal at the cutting point. The upper or lower limit of the working range of the analog-to-digital converter can be represented by the first threshold value. The second threshold value may represent a lower tolerance threshold of the analog-to-digital converter, which represents a minimum size of signal amplitudes. Too large a signal amplitude exceeds the upper and / or lower limit of the operating range and thus the first threshold and the output unit correspondingly reduces the amplitude of the electrical signal with which the exciter winding is operated. Too small an amplitude falls below the second threshold and the output unit increases the amplitude of the electrical signal with which the excitation winding is operated. The output unit can increase / decrease the amplitude of the electrical signal until the component of the sensor signal no longer exceeds / falls below the first / second threshold value.

A preferred embodiment provides that the component whose intensity is determined by means of the monitoring device comprises a DC component of the sensor signal, a maximum value of the sensor signal or a minimum value of the sensor signal. As a result, for example, effects of an asymmetrical shunt on a sensor winding can be mitigated. In addition, the output unit can also shift an offset of the electrical signal accordingly, so z. B. a sensor signal which exceeds the working range unbalanced, z. B. only the upper or only the lower limit, again in the Workspace is "pushed" and thus no longer exceeds the first threshold.

There are application scenarios in which it is advantageous if the component whose strength is detected by means of the monitoring device comprises an amplitude of the sensor signal. In the beginning, error scenarios (such as windings) were mentioned in which, although the sensor signal is not subjected to a disturbing DC component, it still has too small or too large an amplitude. The measure proposed here makes it possible to use the advantages of the invention even in such error scenarios.

It is advantageous if a dependence between the strength of the component of the sensor signal and the amplitude of the electrical signal, in particular the excitation current or the excitation voltage, is at least strictly monotonic, if the strength of the component of the sensor signal is higher than the predetermined first threshold value. By means of such a clear dependence between the strength of the component of the sensor signal and the amplitude of the electrical signal, a reliable and reproducible performance of the resolver is possible if the strength has exceeded the first threshold.

It is also advantageous if a dependence between the strength of the component of the sensor signal and the amplitude of the electrical signal is at least strictly monotonic if the strength of the component of the sensor signal is lower than the predetermined second threshold value. By means of such a clear dependence between the strength of the component of the sensor signal and the amplitude of the electrical signal, a reliable and reproducible performance of the resolver is possible if the strength has fallen below the second threshold value.

Regardless, it is advantageous if the first threshold is greater than the second threshold by a hysteresis value. By such a hysteresis value, a disturbing unnecessary switching back and forth between two operating states can be avoided.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

1 schematically a vehicle with a circuit arrangement having a resolver with a resolver control according to the invention;

2 schematically voltage-time diagrams in a trouble-free operating state of a known resolver;

3 schematically voltage timing diagrams in a disturbed operating state of a known resolver, wherein the disturbance is caused by a shunt of a sensor winding;

4 schematically voltage timing diagrams in an operating state according to the invention of a resolver according to the invention, which is approximately trouble-free, although here is the same shunt as in 3 ;

5 schematically voltage timing diagrams in an operating state according to the invention of a resolver according to the invention, which is approximately free of interference, although here there is a turn circuit of the field winding;

6 schematically voltage timing diagrams in an operating state of a resolver according to the invention, which is approximately free of interference, although there is a winding short circuit of the sensor winding here;

7 schematically a dependence of an amplitude of an exciting current of a strength of a component of a demodulated sensor signal of a resolver;

8th schematically a flow of a method for exciting a resolver.

In the 1 shown circuit arrangement 10 of a vehicle FZ, which is in particular a motor vehicle, comprises a resolver R and a resolver control RS. The resolver R has a stator ST and a rotor RO rotatably mounted with respect to the stator ST. Rotor RO and stator ST have a common main longitudinal axis. Part of the rotor RO is a field winding WE, which rotates in a rotation of the rotor RO together with the rotor RO in the stator ST. Part of the stator ST are a first sensor winding WS with a first (fixed) rotational angular position DP and a second sensor winding WS 'with a second (fixed) rotational angular position DP'. The first DP and the second DP 'angular position differ by 90 °. From the point of view of the common main longitudinal axis, the excitation winding WE and the two sensor windings WS, WS 'are each arranged in a transverse plane. Two of these transverse planes or all three transversal planes may be substantially identical.

The excitation winding WE forms, together with the first sensor winding WS, a first transformer arrangement. Accordingly, the exciter winding WE together with the second sensor winding WS 'forms a second transformer arrangement. A first magnetic coupling degree of the first transformer arrangement is of a rotational angle position α of Exciter winding WE in relation to a (fixed) rotational angle position DP of the first sensor winding WS dependent. Accordingly, a second degree of magnetic coupling of the second transformer arrangement is dependent on the rotational angle position α of the field winding WE in relation to a (fixed) rotational angle position DP 'of the second sensor winding. There is a first DP and a 180 ° rotated second rotational angle position DP + 180 ° of the rotor, in which the amount of the first magnetic coupling degree takes a maximum and the amount of the second magnetic coupling degree takes a minimum. In addition, there is a third angular position DP 'and a rotated by 180 ° fourth angular position DP' + 180 ° of the rotor, in which the amount of the first magnetic coupling degree takes a minimum and the amount of the second degree of magnetic coupling takes a maximum. Between the mentioned angular positions there are intermediate positions in which the degrees of coupling assume intermediate values which lie between minimum and maximum of the respective coupling degree.

The circuit arrangement 10 has a resolver controller RS for controlling the resolver R, the resolver controller RS having an electrical signal generator Q.

An output unit QA of the electrical signal generator Q provides as an electrical signal an excitation current I ready, which is impressed into the excitation winding WE or an excitation voltage U ready, which is applied to the excitation winding WE. A temporal progression of the exciter voltage U or of the excitation current I is sinusoidal and has a frequency with which electrical energy which is fed into the excitation winding can be efficiently transferred to the sensor windings WS, WS 'by means of an alternating magnetic field φ generated thereby.

Moreover, in the 1 as an example of a possible malfunction a shunt of the first sensor winding WS against a supply voltage (for example, terminal 30 ) (see Shunt Resistor RN).

In order to improve immunity to interference and to be able to carry out a demodulation of the (sensor) voltages Us, Us' induced in the sensor windings WS, WS, the resolver control RS has a first and a second analog-to-digital converter AD, AD ' on. The first analog-to-digital converter AD is coupled to the first sensor winding WS and receives the first induced sensor voltage Us and converts these into a digitized sensor voltage Usd. The second analog-to-digital converter AD 'is coupled to the second sensor winding WS' and receives the second induced sensor voltage Us 'and converts it into a second digitized sensor voltage Usd'.

The resolver controller RS further has a first demodulator D coupled to the first analog-to-digital converter AD for amplitude demodulation of the first digitized sensor voltage Usd, the demodulator D outputting a first demodulated sensor signal Sa. Correspondingly, the resolver control RS also has a second demodulator D 'coupled to the second analog-digital converter AD' for amplitude demodulation of the second digitized sensor voltage Usd ', the demodulator D outputting a second demodulated sensor signal Sa'.

The electric signal generator Q has a monitoring unit Vu having a microprocessor and a memory for performing the following functions and storing data such as first and second threshold values SW1 and SW2 and other parameters. The monitoring unit Vü receives a copy of the first and second demodulated sensor signals Sa, Sa 'and analyzes them, as will also be explained below. Through the analysis, the monitoring unit Vü determines whether the first or second demodulated sensor signal Sa, Sa 'or a determined strength of a component of the first or second demodulated sensor signal Sa, Sa' exceeds the first threshold value SW1 or falls below the second threshold value SW2 , as explained above and will be explained below. Accordingly, the monitoring unit Vü outputs a monitoring signal Sü, which is received by the output unit QA coupled to it. The monitoring signal Sü contains information about the determined strength of a component of the first demodulated sensor signal Sa or the second demodulated sensor signal Sa '. This information may represent the strength itself and / or an indication as to whether the component's strength exceeds the first threshold SW1 or falls below the second threshold SW2. As a result, the check as to whether the detected intensity exceeds the first threshold value SW1 or falls below the second threshold value SW2 can take place in the monitoring unit Vü or in the output unit QA. The output unit QA reduces or increases the amplitude of the electrical signal in response to the received monitoring signal S, that is, the output signal QA. H. the excitation current I and the excitation voltage U.

In addition, the resolver controller RS an evaluation circuit AE, which is prepared from the below-explained envelopes Us_, Us'_ of in the two sensor windings WS, WS 'induced voltages Us, Us' the time course of the current angular position α of Rotor RO to determine. The following are for simplicity in only the envelope Us_ and the voltage Us are shown and the voltage Us' and the envelope Us'_ are analogous to the envelope Us_ and voltage Us. The evaluation circuit AE provides at an output AEo a digital or analog signal s (α), which indicates the current angular position α of the rotor RO.

This in 2 The graph shown above shows a sinusoidal time profile of an exciter current I through the field winding WE of a resolver R in an undisturbed operating state. Depending on the respective degrees of coupling, the alternating electric field φ in the sensor windings WS, WS 'induces an electrical voltage Us, Us', which is also approximately sinusoidal and (if the Doppler effect is negligible) has the same frequency as the excitation voltage U. Upon rotation of the rotor RO with a constant rotational speed dα / dt about its main longitudinal axis, a time profile of the degree of coupling of the first sensor winding WS with the excitation winding WE is sinusoidal. The frequency of the coupling degree corresponds to the rotational speed dα / (360 ° dt) of the rotor RO. As a result, the voltage Us induced in the first sensor winding WS at the frequency dα / (360 ° dt) corresponding to the rotation da / dt of the rotor RO is sinusoidally amplitude modulated. The same applies to the second sensor winding WS 'with a phase shift of either 90 ° or 270 °.

That in the middle of the 2 The diagram shown shows the amplitude-modulated voltage Us, which is induced by the alternating magnetic field φ with varying degree of coupling in the first sensor winding WS of the resolver R.

This in 2 The diagram below shows a sinusoidal time profile of the output signal of the first demodulator D. The output signal of the first demodulator D is an envelope Us_ of the voltage Us induced in the first sensor winding WS. This envelope Us_ represents a time course of the first degree of coupling. It is thus a measure of a time profile of a first vector component cos α of the current angular position α of the rotor RO. In this description, envelopes are not unsigned, but they differ in their sign.

Correspondingly, the output signal of the second demodulator D 'is an envelope Us'_ (not shown) of the voltage Us' (not shown) induced in the second sensor winding WS', the envelope Us'_ having a sign inverse to the envelope Us_ and an an corresponds to the horizontal symmetry axis mirrored mirror image of the envelope Us_. The envelope Us'_ of the induced in the second sensor winding WS 'voltage Us' is a time course of the second degree of coupling again. This envelope Us'_ is a measure of a time characteristic of a second vector component sinα of the current angular position α of the rotor RO.

This in 3 The graph shown above shows a sinusoidal time course of an excitation current I through the excitation winding WE of a resolver R in a disturbed operating state of the resolver R when the fault is caused by a shunt of a sensor winding WS and the excitation winding WE of the resolver R from a known electrical energy source with electrical energy is supplied. The impressed excitation current I does not differ from the in 2 shown excitation current.

Like that in 3 shown in the middle of the diagram, the sensor signal Us is offset-shifted in a low-impedance shunt (with a shunt resistance RN of, for example, less than 20 kΩ). If the modulation range (working range) of the digital-to-analog converter AD is largely utilized in trouble-free operation, the offset shift results in exceeding the upper Bo or the lower range limit Bu of the modulation range B.

From the demodulator D the subsequent evaluation unit AE then no longer the faithful modulated signal (the envelope) is provided, but that in the 3 Signal Sa shown below. The information s (α) provided by the evaluation unit AE at its output AEo on the current angular position α of the rotor RO are then more or less faulty depending on the degree of overdriving the analog-to-digital converter AD. This in turn can result in error-free operation of the machine or of the vehicle in which the resolver R is used is no longer possible.

In principle, it would be possible (as a precaution for such error cases) to change (adapt) the voltage Us at the input of the analog-to-digital converter AD as such (that is, on the development side) such that an overdrive of the analog-to-digital converter AD also occurs in the case of such offset shift does not occur. However, this would have the disadvantage that in undisturbed operation for generating the digitized signal Usd to be evaluated, only a smaller part of the quantization levels (that is, not the previously used resolving power) of the analog-to-digital converter AD would be usable. This would result in a disadvantageous deterioration of a signal-to-noise ratio, which is undesirable for undisturbed operation and may still be tolerable in emergency operation.

This in 4 The diagram above shows a sinusoidal time course of a Exciter current I through the exciter winding WE a resolver R in an operating state of the resolver R according to the invention, which is approximately trouble-free, although here the same shunt of the sensor winding WS is present as in 3 , In this case, the sensor signal or the sensor voltage Us was shifted back into the modulation range B of the analog-to-digital converter AD by means of a change in the amplitude U of the excitation voltage U. In this way, an offset-free recovery of the modulated angle information α (t) and an error-free calculation of the angular position α (t) of the rotor RO can also take place in the disturbed operation of the resolver R (for example in the case of a shunt of a sensor winding WS).

If the electrical signal generator Q is set up to detect when there is no longer a fault (for example, the bypass is no longer present), it can also be set up to increase the amplitude U of the excitation voltage U again and thus to the undisturbed operating mode return if she realizes that there is no longer a fault.

The 5 shows voltage-time diagrams in an operating state according to the invention of the resolver R, which is approximately trouble-free, although there is a turn-circuit of the excitation winding WE here. Since the voltage transmission ratio WS / WE, WS '/ WE of a transformer (here the resolver R) depends on the Windungszahlverhältnis between primary winding (here WE) and secondary winding (here WS or WS') and a winding short circuit of the field winding WE as a result of a reduction the number of turns of the primary winding of a transformer is the same, the short circuit of the exciter winding WE always leads to an increase in the amplitude ^ Us of the sensor voltage Us. To compensate for this, the electrical signal generator Q of the resolver control RS reduces the amplitude ^ I of the excitation current I, so that the amplitude Us Us of the sensor voltage Us is again in the control range B.

The 6 shows voltage time diagrams in an operating state according to the invention of the resolver R, which is approximately free of interference, although there is a turn-circuit of the sensor winding WS here. A short circuit of the sensor winding WS is equal to the result of a reduction in the number of turns of the secondary winding of a transformer. The winding short circuit of the secondary winding WS therefore always leads to a reduction of the amplitude .mu.s of the sensor voltage Us, which causes a signal-to-noise ratio of the sensor voltage Us to deteriorate. To compensate for this, the electrical signal generator Q increases the resolver RS the amplitude ^ I of the excitation current I, so that the amplitude ^ Us of the sensor voltage Us largely exploits the modulation range B and the signal-to-noise ratio is improved.

7 shows a dependence of an amplitude ^ I of an excitation current I of a magnitude | S | of a component (here a DC component) of a demodulated sensor signal Sa of a resolver R. If the DC component | S | of the demodulated sensor signal Sa exceeds a predetermined first threshold SW1, the electrical signal generator Q of the resolver control RS reduces the amplitude ^ I of the exciting current I. When the DC component | S | of the demodulated sensor signal Sa falls below a predetermined second threshold value SW2, the electrical signal generator Q of the resolver control RS increases the amplitude I of the excitation current I. In order to avoid oscillation, it is expedient for the first threshold value SW1 to be greater by a hysteresis value HW as the second threshold SW2.

This in 8th shown method 100 for energizing a resolver R can from the electrical signal generator Q, z. B. by a microprocessor of the monitoring unit Vü and / or the output unit QA are executed. In a first step 111 . 112 the excitation winding WE of the resolver R is operated by impressing an electrical signal in the form of an excitation current I in the exciter winding WE or in the form of an excitation voltage U is applied to the field winding WE.

In a second step 120 a sensor voltage Us of the sensor winding WS is detected. In a third step 130 For example, after a conversion into a digitized sensor signal Usd by means of demodulation of the detected sensor voltage Us, a demodulated sensor signal Sa is generated. In a fourth step 140 becomes a strength | S | a component of the demodulated sensor signal Sa determined. In a fifth step 150 a monitoring signal S u is generated which contains information about the determined strength | S | of the component of the sensor signal Sa includes. In a sixth step 161 is an amplitude ^ U of the excitation current I or the excitation voltage U in response to the monitoring signal Sü reduced when the determined strength | S | of the component of the demodulated sensor signal Sa exceeds a predetermined first threshold value SW1. Alternatively, in the sixth step 162 amplifies an amplitude ^ U of the excitation current I or the excitation voltage U as a function of the monitoring signal S, if the determined strength 151 the component of the demodulated sensor signal Sa falls below a predetermined second threshold value SW2.

The above method has been exemplary for the sensor voltage Us of the first sensor winding WS explained, where it is analogous to the sensor voltage Us 'of the second sensor winding WS'.

LIST OF REFERENCE NUMBERS

10

circuitry

AD

Analog to digital converter

AD '

Analog to digital converter

AE

evaluation

AEo

Output of the evaluation unit

Bo

upper limit of the work area

Bu

lower limit of the workspace

D

first demodulator

D '

second demodulator

DP

Angular position of the first sensor winding

DP '

Angular position of the second sensor winding

FZ

vehicle

HW

hysteresis

1

excitation current

^ I

Amplitude of an excitation current

Q

electrical energy source

QA

Output unit of the power source

R

resolver

RN

Shunt resistor

RO

rotor

RS

Resolver Control

Sat.

first demodulated sensor signal

Sa '

second demodulated sensor signal

| S |

Strength of the component of the sensor signal

ST

stator

sweet

heartbeat

SW1

first threshold

SW2

second threshold

s (α)

Output signal of the evaluation unit

t

Time

^ U

Amplitude of an excitation voltage

^ Us

Amplitude of the first sensor voltage

Us

first sensor voltage

usd

first digitized sensor voltage

Us_

Envelope of the first sensor voltage

Us'

second sensor voltage

usd '

second digitized sensor voltage

vii

monitoring device

WE

excitation winding

WS

first sensor winding

WS '

second sensor winding

α

angle of rotation

100

method

111

Imprinting an excitation current

112

Applying an excitation voltage

120

Detecting a sensor voltage

130

Generating a demodulated sensor signal

140

Determining a strength of a component of a sensor signal

150

Generating a monitoring signal

161

Reducing an amplitude of an excitation current or excitation voltage in response to the monitoring signal

162

Reducing an amplitude of an excitation current or excitation voltage in response to the monitoring signal

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 1298298 A [0005]

Claims (9)

Electrical signal generator (Q) for operating a field winding (WE) of a resolver (R), wherein the resolver (R) at least one sensor winding (WS, WS '), in response to the operation of the field winding (WE) a sensor voltage (Us Spends, Us'), marked by - A monitoring device (Vü), for receiving a sensor voltage (Us, Us') representing the sensor signal (Sa, Sa '), for determining a strength (| S |) of a component of the sensor signal (Sa, Sa') and for generating a monitoring signal (S u) is formed, which contains information about the determined strength (| S |) of the component of the sensor signal (Sa, Sa '); and - An output unit (QA), which is adapted to provide an electrical signal (I, U) for operating the excitation winding (WE) and in response to the monitoring signal (Sü) an amplitude (^ I, ^ U) of the electrical signal (I , U), if the determined strength (| S |) of the component of the sensor signal (Sa, Sa ') exceeds a predetermined first threshold value (SW1) and / or an amplitude (^ I, ^ U) of the electrical signal (I, U) to increase when the determined strength (| S |) of the component of the sensor signal (Sa, Sa ') below a predetermined second threshold value (SW2). Electrical signal generator according to claim 1, wherein the component whose intensity (| S |) is determined by means of the monitoring device (Vü), a DC component of the sensor signal (Sa, Sa '), a maximum value of the sensor signal (Sa, Sa') or a minimum value of the sensor signal (Sa, Sa '). An electric signal generator according to claim 1 or 2, wherein the component whose intensity (| S |) is detected by the monitoring device (Vü) has an amplitude (^ Sa) of the sensor signal (Sa, Sa '). An electric signal generator according to any one of claims 1 to 3, wherein a dependency between the strength (| S |) of the component of the sensor signal (Sa, Sa ') and the amplitude (^ I) of the electrical signal (I, U) is strictly monotone, when the strength (| S |) of the component of the sensor signal (Sa, Sa ') is higher than the predetermined first threshold value (SW1). An electric signal generator according to any one of claims 1 to 4, wherein a dependency between the strength (| S |) of the component of the sensor signal (Sa, Sa ') and the amplitude (^ I) of the electrical signal (I, U) is strictly monotonic. when the strength (| S |) of the component of the sensor signal (Sa, Sa ') is lower than the predetermined second threshold value (SW2). Electrical signal generator according to one of claims 1 to 5, wherein the first threshold value (SW1) by a hysteresis value (HW) is greater than the second threshold value (SW2). Circuit arrangement ( 10 ) with a resolver (R), which has a field winding and at least (WE) a sensor winding (WS, WS '), and with a resolver control (RS), wherein the resolver control (RS) an electrical signal generator (Q) according to one of the preceding claims and at least one analog-to-digital converter (AD, AD ') is coupled to the at least one sensor winding (WS, WS') for receiving the sensor voltage (Us, Us') and wherein the first (SW1 ) and / or the second threshold (SW2) represent an operating range of the at least one analog-to-digital converter (AD, AD '). Motor vehicle (FZ) with a circuit arrangement ( 10 ) according to claim 7. Method for operating a resolver (R), wherein the resolver (R) has a field winding (WE) and at least one sensor winding (WS, WS ') which generates a sensor voltage (Us, Us') in response to the operation of the field winding (WE). ), the method ( 100 ) comprises the following steps: - operating ( 111 . 112 ) of the excitation winding (WE) with an electrical signal (U, I); - To capture ( 120 ) of the sensor voltage (Us, Us'); - Produce ( 130 ) of a sensor signal (Sa, Sa ') based on the detected sensor voltage (Us, Us'); characterized by the steps: - determining ( 140 ) a strength (| S |) of a component of the sensor signal (Sa, Sa '); - Produce ( 150 ) a monitoring signal (S u) containing information about the detected strength (| S |) of the component of the demodulated sensor signal (Sa, Sa '); - Reduce ( 161 ) of an amplitude (U U) of the electrical signal (I, U) as a function of the monitoring signal (S)), when the determined strength (S S |) of the component of the sensor signal (Sa, Sa ') exceeds a predetermined first threshold value (SW1) , and / or - Enlarge ( 162 ) an amplitude (^ U) of the electrical signal (I, U) in response to the monitoring signal (Sü), when the determined strength (| S |) of the component of the sensor signal (Sa, Sa ') below a predetermined second threshold value (SW2) ,

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